CO_2 efflux from different forest soils and impact factors in Dinghu Mountain, China

摘要

CO_2 fluxes from soils and related environmental factors were measured in three forest ecosystems of Dinghu Mountain using static chamber-gas chromatograph technique for one year. The seasonal pattern of CO_2 flux, contribution of litter on total CO_2 flux and the correlations of CO_2 flux with soil temperature and soil water content were examined for each type of forest. The results were given as followings: (1) The seasonal patterns of CO_2 flux from soil of the three types of forest were similar, with a higher CO_2 flux in rainy season than in dry season. The comparative relations of mean annual CO_2 fluxes between the three sites were expressed as: monsoon forest > mixed forest > pine forest. (2) CO_2 fluxes from litter decomposition in monsoon forest, mixed forest and pine forest accounted for 24.43%, 41.75% and 29.23% of the corresponding total CO_2 fluxes from forest floor, respectively. (3) Significant relationships were found between CO_2 fluxes and soil temperatures at 5 cm depth for the three types of forest, which could be best described by exponential equations. The calculated Q_(10) values based on soil temperature at 5 cm depth ranged from 1.86 to 3.24. More significant relationships were found between CO_2 fluxes and soil water content when the annual variation coefficients of soil moisture were higher.